const path = require("path");
const MiniCssExtractPlugin = require('mini-css-extract-plugin')
const CssMinimizerPlugin = require("css-minimizer-webpack-plugin");
const HtmlWebpackPlugin = require('html-webpack-plugin')
const ESLintPlugin = require('eslint-webpack-plugin')
const CopyWebpackPlugin = require("copy-webpack-plugin")
/* 
  esLint配置过程:
    1. 下载eslint
    2. 在项目根目录创建.eslintrc.json文件,并进行配置
    3. 下载 eslint-webpack-plugin 插件
    4. 引入并使用这个插件
*/
module.exports = {
  //入口文件路径
  entry: path.resolve(__dirname, "../src/index.js"),

  //出口配置
  output: {
    path: path.resolve(__dirname, "../build"),
    filename: "./js/bundle.js"
  },

  //loader配置
  module: {
    rules: [{
        /* 
          test:后边配置的是一个正则表达式,用来匹配文件名是否符合当前loader的条件
        */
        test: /\.css$/i,
        /* 
          css-loader:为了识别css类型文件进行打包
          style-loader:js把样式放在style标签中,并插入到页面中
          use后如果是一个数组,则是从后向前一致加载
        */
        use: [MiniCssExtractPlugin.loader, "css-loader"],
      },
      {
        /* 
          test:后边配置的是一个正则表达式,用来匹配文件名是否符合当前loader的条件
        */
        test: /\.less$/i,
        /* 
          less-loader:识别less文件类型
          css-loader:为了识别css类型文件进行打包
          style-loader:js把样式放在style标签中,并插入到页面中
          use后如果是一个数组,则是从后向前一致加载
        */
        use: [MiniCssExtractPlugin.loader, "css-loader", "less-loader"],
      }, {
        test: /\.(png|jpg|gif|webp)$/,
        //asset 在导出一个 data URI 和发送一个单独的文件之间自动选择。代替之前的url-loader和file-loader
        type: "asset",
        parser: {
          dataUrlCondition: {
            maxSize: 30 * 1024, // 小于30kb以下的图片会被打包成base64格式
          },
        },
        generator: {
          filename: 'images/[name][ext]'
        }
      },
    ],
  },

  //优化的配置
  optimization: {
    minimizer: [
      new CssMinimizerPlugin(),
    ],
  },

  //插件的配置
  plugins: [new MiniCssExtractPlugin({
    filename: "./css/main.css"
  }), new HtmlWebpackPlugin({
    template:path.resolve(__dirname,"../public/index.html"),
    filename: "index.html",
    minify: {
      collapseWhitespace: true,
      keepClosingSlash: true,
      removeComments: true,
      removeRedundantAttributes: true,
      removeScriptTypeAttributes: true,
      removeStyleLinkTypeAttributes: true,
      useShortDoctype: true
    }
  }), new ESLintPlugin({
    fix: true
  }), new CopyWebpackPlugin({
    patterns: [{
      from: path.resolve(__dirname,"../public"),
      to: "public",
      //配置复制时忽略的文件
      globOptions: {
        ignore: ["**/index.html"]
      }
    }],
  }), ],


  //模式
  mode: "production"
}